I want to use my arduino UNO to make a decode device. I found an example code and a some steps which can teach me how to build. In those steps, it told me that I need to download a folder called IRremote and install it in this route /Users/username/Documents/Arduino/libraries.

When I finished write the coding and tried to verify, Arduino IDE said that 'IRrecv' does not name a type.

/Users/TommyHu/Downloads/Arduino.app/Contents/Resources/Java/hardware/tools/avr/bin/avr-g++ -c -g -Os -Wall -fno-exceptions -ffunction-sections -fdata-sections -mmcu=atmega328p -DF_CPU=16000000L -MMD -DUSB_VID=null -DUSB_PID=null -DARDUINO=103 -I/Users/TommyHu/Downloads/Arduino.app/Contents/Resources/Java/hardware/arduino/cores/arduino -I/Users/TommyHu/Downloads/Arduino.app/Contents/Resources/Java/hardware/arduino/variants/standard /var/folders/40/qp_yf07j11z_nb9qwcs2fgd40000gn/T/build6216189189652123984.tmp/sketch_mar03a.cpp -o /var/folders/40/qp_yf07j11z_nb9qwcs2fgd40000gn/T/build6216189189652123984.tmp/sketch_mar03a.cpp.o sketch_mar03a.ino:2:21: warning: IRremote.h: No such file or directorysketch_mar03a.ino:2:21: warning: IRremote.h: No such file or directorysketch_mar03a:6: error: 'IRrecv' does not name a typesketch_mar03a:6: error: 'IRrecv' does not name a typesketch_mar03a:7: error: 'decode_results' does not name a typesketch_mar03a:7: error: 'decode_results' does not name a typesketch_mar03a.ino: In function 'void setup()':sketch_mar03a:11: error: 'irrecv' was not declared in this scopesketch_mar03a.ino: In function 'void setup()':sketch_mar03a:11: error: 'irrecv' was not declared in this scopesketch_mar03a.ino: In function 'void loop()':sketch_mar03a.ino: In function 'void loop()':sketch_mar03a:15: error: 'irrecv' was not declared in this scopesketch_mar03a:15: error: 'irrecv' was not declared in this scopesketch_mar03a:15: error: 'results' was not declared in this scopesketch_mar03a:15: error: 'results' was not declared in this scopesketch_mar03a:15: error: expected `)' before '{' tokensketch_mar03a:15: error: expected `)' before '{' tokensketch_mar03a:21: error: expected primary-expression before '}' tokensketch_mar03a:21: error: expected primary-expression before '}' tokensketch_mar03a:21: error: expected `;' before '}' tokensketch_mar03a:21: error: expected `;' before '}' token